Chair for use in medical treatment



Sept. 5, 1939. N. HARA 2,172,063

CHAIR FOR USE IN MEDICAL TREATMENT I Filed Jan. 28, 1936 2 Sheets-Sheet l IN VEN TOR.

- NOPUSHIRO HARA B www ATTORNEYS.

Sept. 5, 1939. HARA 2,172,063

CHAIR FOR USE IN MEDICAL TREATMENT Filed Jan. 28, 1936 2 Sheets-Sheet 2 @Q NOBUSH/RO HA RA mwyg I ATTORNEYS.

Patented Sept. 5, 1939 UNITED stares PATENT oFFicE Application January 28, 1936, Serial No. 61,120 In Japan April 5, 1935 2 Claims. to]. 155-26) The present invention relates toan improvement in chairs for use in medical treatment, especially dental chairs, one of its objects being to obtain cheaply a chair of durable construction having a seat capable of rocking lightly and briskly and also able to be locked in a regulating position simply and securely.

Referring to the accompanying drawings which show as an example one embodiment of the chair according to this invention,

Figure 1 is a front view;

Figure 2 is a side view;

Figure 3 is an enlarged partly sectional side view;

Figure {l is a sectional side view of the seat locking mechanism;

Figure 5 is a sectional plan of the same;

Figure 6 is a detail showing the condition in which the seatsupporting frame is rocked;

Figure '7 is a perspective view of the wedge piece;

Figure 8 is a perspective view of the movable wedge; 7

Throughout the views, the same reference numerals indicate the same or corresponding parts.

In the practice of my invention, a base flange I has a base 2 surmounted by a pedestal 3 from which a vertical tube 6 extends which carries a detachable disc or plate 1. Within the tube 8 is a piston rod 9 which is screwed into a cap or the like H] which in turn, is secured as by a thread 31 in the upper end of tube 6, and said rod 9 may be directly lowered or raised by operating a release lever 28 or by pumping by re- 35 peatedly actuating a plunger lever 29 in more or less conventional manner by means within the base and pedestal which are not shown as the same form no direct portion of the invention a such.

L0 Adjacent to the upper end of the tube 6 is a spring box 40 which cooperates with the upper end of a rod 35 projecting upwardly from the top of pedestal 3, by making contact with and engaging against said rod so as to utilize said L5 box as a resilient stop for the seat, and thus prevent sudden shocks or jars when the chair is lowered. The spring box 40 is telescoping in construction and contains a compression spring 40 tending to resist compression and telescoping of said box;

A seat supporting frame 44 is supported swingably by the bolts 43 screwed in the disc I which has a bifurcated arm 45 extending beyond it. Said bifurcated arm is provided at its inside 5 with a guide member 46 of U-shaped section supported swingably by a spindle 41 and. having within its U-s'haped inner deep portion a semicircular longitudinal groove 48, opposite which is fixed a wedge member 49 shown in Figure 7. The said wedge member 49 is provided with planes 5 58 inclined in opposite directions, at the middle of which is arranged a movable-wedge 5| with a plane 4! having the greater inclination and also a shaft 52 projecting outward, so that it may be moved inwardly by pressing the end of the said 10 shaft 52 by an arm 55 formed integrally with a pedal 54 loosely mounted on the bifurcated arm 45 at a pivot 53. On the inner surface of the front end of the seat supporting frame 44 is provided a bracket 56 having a sliding rod 58 15 pivoted thereto by means of a shaft 57, said rod 58 consisting of a rod of circular section with one side 59 planed and being slidable freely with regard to the guide member 46, guided by the groove 48. Rolls 60 are inserted between the 20 planed surface 59 and inclined planes 50 and 4| of the wedge member 49 and movable wedge 5!, said rolls being pressed against said inclined planes and planed surface 59 of the rod 58 through a spring 62 by bolts 6| screwed adjustably 25 in the upper and lower parts of the wedge member 49, so as to lock the sliding rod 58.

If in Figure 4 the pedal 54 is' pressed down, the wedge 5| is pressedinwardly, so that its inclined plane 41 moves the rolls 60 apart against the 30 action of the spring 62 thus to release the sliding rod 58 into a movable condition in which the seat supporting frame 44 may be rocked backward with the bolt 43 as its center (see Figure 6). If the pedal is let free when the seat support- 35 ing frame 44 has reached the proper inclination, the rolls 60 are pushed in between the inclined plane of the wedge 5| and the planed surface 59 of the sliding rod 58 pressing the wedge 5! by the spring '62, so that said sliding rod 58 is 40 locked in its position. In the above device, if the seat vibrates, the rolls 60 have a tendency to enter between the wedge 5| and planed surface I9 more deeply and therefore the seat may be locked tightly with a desired inclination, thus removing 45 the fear of the locking means getting loosened by the locking of the seat. o

The seat supporting frame 44 is provided with a rigid rearwardly extending guide arm 66 partly supporting the adjustable back frame 69 which 50 has a pair of side arms 10 pivoted at the sides to frame 44, adjustment of the back being more or less conventionally accomplished by means of a lever or handle 80.

To the seat supporting frame 44 is secured a rigid step 85', to the front end of which is pivoted a foot plate 81, while a pendent lever portion 90 upon said foot plate is connected to an adjusting leverl92 by means of a link 93, so that said footplate may be adjusted in somewhat conventional manner which it is not necessary to explain further, as this adjustment, as well as that of the back and the operation of elevating or lowering the seat structure as a whole do not go to the heart of the invention.

Having now fully described my invention, I claim:

1. In a dental chair or the like having a vertical member projecting upwardly and surmounted by a platform, and a seat frame tiltably mounted upon said platform, and means for locking said seat in adjusted position comprising the combination of a bifurcated arm rigid with and projecting forwardly from said platform, a guide member pivoted within said bifurcated arm, a rod pivoted to the frame of the seat and slidable within said guide member, a wedge member having inclined faces terminating in a position opposite to said slidable rod and'adjacent thereto, said wedge member being fitted Within and secured to said guide member, circular bearing elements interposed within said wedge member between said movable wedge and the slidable rod, and resilient means bearing against a stationary portion of the wedge member and urging the bearing elements in a direction which causes the same to wedge between the inclined faces of said wedge member and said slidable rod, and means for releasing said locking means comprising a movable wedge slidably mounted between said bearing elements and means for sliding said movable wedge to cam said bearing elements out of engagement with said rod.

2. A dental chair or the like according toclaim 1, having adjustable means for adjusting the resilient means which is associated with the circular bearing elements.

NOBUSHIRO HARA, 

